Cooler in diesel line. Why? -
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Unread 02-05-2012, 08:05 AM   #1
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2004 WJ 
Join Date: Feb 2011
Location: Bognor, West Sussex. England. Great Britain
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Cooler in diesel line. Why?

I ran over a brick yesterday and whilst I was checking underneath (no damage luckily) I noticed a smal cooler (like an oil cooler) in the diesel return line, near the tank - factory fit. Never noticed it before. Why is it there. Does the diesel get that hot in the fuel rail that it has to be cooled before going bask into the tank??

Just curious.

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Unread 02-05-2012, 08:43 AM   #2
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Fuel in deisel systems is constantly circulating and gets warm from the heat of the engine, the cooler counteracts this.
Think like this, fuel expands when it warms up and contracts when it cools, the cooler the fuel/air the more power your engine makes.
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Unread 02-05-2012, 09:25 AM   #3
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I noticed the same thing on mine. I also noted that it was well....very exposed to the elements and didn't think it would take much to damage it... I don't think its that clever a design.
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